Consider the following exchange:
You: "Hey, how's it going?"
Them: "Not bad, how about you?"
You: "Oh, pretty good."
Do you have this conversation with
a) your roommate,
b) someone you just met, or
c) someone you know, but not well?
If I'm any judge of the human condition, the answer is generally C: the person you know, but not well, or at least not well enough to have anything to talk about with. Funny how that works, ain't it?
I went to a wedding last weekend. (It was wonderful.) At the reception, I sat next to someone who knew literally no one there except the bride and maid of honor, who were both otherwise occupied, so the duty of conversation-making was left in my hands. And I was fine with that. I love talking to strangers because there's no shortage of topics available: I was able to ask about her job, her school, her family, and so on, all as part of a perfectly natural getting-to-know-each-other conversation.
Now, think of someone you've known for at least a year but never really gotten to know, and imagine plunking yourself down next to them and having that same conversation. Awkward. For reason, the length of time I've known someone and the ease with which I get to know them often wind up inversely, not directly, proportional.
It's human instinct to revert to topics where we already know at least a little bit about the other person, hence the number of homework-related conversations that go on at NSA every day of the school year. I may not know how many siblings you have or what your favorite movie is, but I do know that we both have the same massive reading assignment due this week. If you don't go to NSA, I might have to resort to that final frontier of conversations desperate for adventure: the weather. Topics like these are where small talk goes to die.
You: "So... how's that Doctrine of the Christian Life going?"
Them: "Dude, I still have to read 600 pages tonight."
You: "That sucks."
[awkwad silence, reprise]
Back during the school year, my roommate caught my attention by saying something to the effect that you know you had a good time at someone's house when you didn't just sit around talking about school. I think that's the hallmark of friendship, or at least friendship in the making: knowing the other person well enough to have something unique to talk to them about.
In fact, this argument proves its own point, since by setting out to defend small talk, I'm making indirect small talk with a friend who recently commented on how much they dislike small talk in the first place. If we weren't friends, it would just be awkward.